Image pickup apparatus and image processing method

ABSTRACT

An image pickup apparatus for picking up an image of a target object in divisions as a plurality of partial images which overlap by a predetermined quantity, is provided with a field angle setting unit configured to set a field angle with which the target object is to be picked up, a display unit for displaying an image, and an image generating unit for generating the partial images to be displayed on the display unit by dividing an image of the target object which is picked up with the field angle.

BACKGROUND OF THE INVENTION

This application claims the benefit of a Japanese Patent ApplicationNo.11-305233 filed Oct. 27, 1999, in the Japanese Patent Office, thedisclosure of which is hereby incorporated by reference.

1. Field of the Invention

The present invention generally relates to image pickup apparatuses andimage processing methods, and more particularly to an image pickupapparatus which picks up an image in divisions and to an imageprocessing method which processes the image which is picked up indivisions.

2. Description of the Related Art

Digital cameras have become increasingly popular. The increasingpopularity of the digital camera was gained by the ease with which theimage can be processed as digital information, matching the recent trendof processing various kinds of data electronically. In addition, itwould be extremely troublesome to convert the image which is picked upby a conventional camera using a silver film into the digitalinformation.

The digital camera can be used in various applications to bring out theadvantageous features thereof. However, the resolution of the imagewhich is picked up by the digital camera is not as high compared to thatpicked up by the conventional camera using the silver film. Althoughrecently, the number of pixels of a CCD image pickup element used in thedigital camera has increased, it is still not large enough for pickingup extremely fine characters and patterns with a satisfactoryreproducibility.

Accordingly, a method has been proposed to obtain partial images bypicking up parts of a target object with a narrow field angle, andcombining the partial images to generate a full image of the targetobject, which is as if the image were picked up by a high-density imagepickup element having a large number of pixels with a wide field angle.When generating a high definition image by this proposed method, thefollowing points are very important when picking up the partial images.

First, each part of the target object must be included in one of thepartial images. If a certain part of the target object is missing fromall of the partial images, the full image which is generated bycombining the partial images will naturally be missing this certainpart. Second, each partial image must have a region which overlaps anadjacent partial image. The partial images are combined based on imageinformation of such overlapping regions. Generally, the accuracy of theimage combining process improves as the overlapping regions becomelarger, but the number of partial images to be picked up consequentlyincreases, to thereby increase the time required to carry out the imagecombining process.

Accordingly, when picking up the partial images of the target object,each part of the target object must be picked up, and in addition, theoverlapping regions must be provided in an appropriate number of partialimages. However, such an operation requires a skilled operator toperform, and furthermore, such an operation is extremely troublesome toperform. In view of the above, various methods have been proposed topick up the partial images that will not put such a burden on theoperator who operates the image pickup apparatus.

For example, a Japanese Laid-Open Patent Application No.11-75108proposes a method which facilitates generation of a combined image 190shown in FIG. 1A by overlapping a partial image 191 shown in FIG. 1Bwhich is already picked up and a partial image (through-image) 195 shownin FIG. 1C which is to be picked up or, time-divisionally displaying animage 199 shown in FIG. 1D. By displaying the partial images 191 and 195on a monitor by overlapping a right end portion A of the partial image191 and a left end portion A′ of the partial image 195, the operatoradjusts an image pickup range (through-image) of a camera so that theoverlapping portions A and A′ match, and records the combined image.

On the other hand, a Japanese Laid-Open Patent Application No.10-186551proposes a method which compares a portion of the partial image which isalready picked up and a portion of the present through-image, andrecords the through-image as one of the partial images if the twocompared images match. In addition, this proposed method picks up thefull image of the target object, displays the position of the presentthrough-image on the full image, and also displays the position of thepartial image which is already picked up on the full image. As a result,this proposed method assists the operation to pick up the partial imagesso that the overlapping regions of the partial images positively existand no missing partial image of the target object exists.

However, according to the method proposed in the Japanese Laid-OpenPatent Application No.11-75108, the overlapping regions of the partialimages 191 and 195 are displayed, and for this reason, it is difficultto detect a characterizing feature in the overlapping regions if similarimage information continues in the vicinity of the overlapping regions,as described below in conjunction with FIGS. 2A through 2C.

For example, it is assumed for the sake of convenience that the image ofa target object 1 shown in FIG. 2A is picked up in two divisions,namely, a left partial image 2 shown in FIG. 2B corresponding to theleft part of the target object 1 and a right partial image shown in FIG.2C corresponding to the right part of the target object 1. A rightportion B of the left partial image 2 is displayed in an overlappingmanner on a left portion C of the right partial image 3 on the display.However, the image information in the right portion B is substantiallythe same in the horizontal direction for virtually the entire rightportion B, and a position in the right portion B cannot be specified. Asa result, it is extremely difficult for the operator to accuratelyoverlap the left and right partial images 2 and 3 so that the right andleft portions B and C perfectly match.

On the other hand, when combining the partial images arranged in onedirection, as in the case of a panoramic image, a predetermined one ofright, left, top and bottom end portions of the partial images isautomatically displayed. But in a case where the image of the targetobject is picked up in four divisions, namely, a top right partial image4, a bottom left partial image 5, a bottom right partial image 6 and atop right partial image 7 shown in FIG. 3, for example, it is extremelydifficult to automatically judge the overlapping end portions of thepartial images 4 through 7. For example, if the partial image 4 ispicked up first, and the end portion of this partial image 4 is to bedisplayed in an overlapping manner on the end portion of the partialimage (through-image) which is to be picked up next, the end portion tobe overlapped differs depending on whether the partial image 5 or thepartial image 7 is to be picked up next. It is extremely difficult toautomatically judge the end portion to be overlapped, and it is alsoextremely troublesome to manually specify the end portion to beoverlapped.

Furthermore, when displaying not only a portion of the image but all ofthe partial images which are picked up in an overlapping manner, nooperation is actually carried out to overlap the end portions. Hence,the operator must carry out a troublesome operation of picking up thethrough-image while carefully confirming the display on the monitor thecorrespondence of the left end portion of the through-image and theright end portion of the partial image which is already picked up, forexample. In addition, since the display is made on the monitor by onlyfocusing on the overlap between two partial images at two successiveimage pickup times, the image pickup times do not become consecutivewhen picking up three or more partial images, and it is impossible toconfirm the overlap between the adjacent partial images displayed on themonitor. In other words, in the case of the target object shown in FIG.3, if the partial images 4, 5, 6 and 7 are picked up in this order, itis impossible to confirm the overlap of the partial images 4 and 7,because the image pickup times of these partial images 4 and 7 are notconsecutive. Therefore, the method proposed in the Japanese Laid-OpenPatent Application No.11-75108 is not suited for a case where the imageof the target object is picked up in divisions such that the adjacentpartial images do not become continuous in time.

On the other hand, according to the method proposed in the JapaneseLaid-Open Patent Application No.10-186551, the problems of the methodproposed in the Japanese Laid-Open Patent Application No.11-75108 areunlikely to occur, since the overlap of the partial images is judgedautomatically. However, it is necessary to confirm the overlap of thethrough-image with respect to all of the partial images which arealready picked up, and an extremely large amount of data processing isrequired for this confirmation. As a result, the required processingtime increases, and the cost of the image pickup apparatus alsoincreases. Moreover, there is a limit in the existing processingaccuracy with which the overlap of the through-image and the partialimage which is already picked up is confirmed, and the reliability ofthis confirmation process is not very high. Furthermore, there is a highpossibility that a part of the image of the target object will not bepicked up, since it is impossible to know which partial images havealready been picked up.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to providea novel and useful image pickup apparatus and image processing method,in which the problems described above are eliminated.

Another and more specific object of the present invention is to providean image pickup apparatus for picking up an image of a target object indivisions as a plurality of partial images which overlap by apredetermined quantity, comprising display means for displaying animage, and partial image generating means for generating the partialimages to be displayed on the display means by dividing a full image ofthe target image which is picked up in advance into predetermined sizesusing information related to an overlap of the partial images. Accordingto the image pickup apparatus of the present invention, it is possibleto realize an image pickup apparatus which can generate ahigh-definition image by combining the partial images obtained bypicking up the target object in divisions. In addition, it is possibleto secure the necessary overlapping region that is required whencombining the partial images, and to instruct the operator of the partsof the target object to be picked up so that all parts of the targetobject are picked up without dropout of image information.

A further object of the present invention is to provide an image pickupapparatus for picking up an image of a target object in divisions as aplurality of partial images which overlap by a predetermined quantity,comprising a display unit displaying an image, and a generating unitgenerating the partial images to be displayed on the display unit bydividing a full image of the target image which is picked up in advanceinto predetermined sizes using information related to an overlap of thepartial images. According to the image pickup apparatus of the presentinvention, it is possible to realize an image pickup apparatus which cangenerate a high-definition image by combining the partial imagesobtained by picking up the target object in divisions. In addition, itis possible to secure the necessary overlapping region that is requiredwhen combining the partial images, and to instruct the operator of theparts of the target object to be picked up so that all parts of thetarget object are picked up without dropout of image information.

Another object of the present invention is to provide an image pickupapparatus for picking up an image of a target object in divisions as aplurality of partial images which overlap by a predetermined quantity,comprising field angle setting means for setting a field angle withwhich the target object is to be picked up, display means for displayingan image, and partial image generating means for generating the partialimages to be displayed on the display means by dividing a full image ofthe target image which is picked up with a predetermined field angle setby the field angle setting means into predetermined sizes using thepredetermined field angle and information related to an overlap of thepartial images after the predetermined field angle is set by the fieldangle setting means. According to the image pickup apparatus of thepresent invention, the two images which are displayed in the overlappingmanner in the full image are approximately the same, so that the effectof positioning or aligning the two images by the overlapping display islarge.

Still another object of the present invention is to provide an imagepickup apparatus for picking up an image of a target object in divisionsas a plurality of partial images which overlap by a predeterminedquantity, comprising a field angle setting unit setting a field anglewith which the target object is to be picked up, a display unitdisplaying an image, and a partial image generating unit generating thepartial images to be displayed on the display unit by dividing a fullimage of the target image which is picked up with a predetermined fieldangle set by the field angle setting unit into predetermined sizes usingthe predetermined field angle and information related to an overlap ofthe partial images after the predetermined field angle is set by thefield angle setting unit. According to the image pickup apparatus of thepresent invention, the two images which are displayed in the overlappingmanner in the full image are approximately the same, so that the effectof positioning or aligning the two images by the overlapping display islarge.

A further object of the present invention is to provide an imageprocessing method for processing an image of a target object which ispicked up by an image pickup apparatus in divisions as a plurality ofpartial images which overlap by a predetermined quantity, comprising thesteps of (a) displaying an image, and (b) generating the partial imagesto be displayed by the step (a) by dividing a full image of the targetimage which is picked up in advance into predetermined sizes usinginformation related to an overlap of the partial images. According tothe image processing method of the present invention, it is possible torealize an image pickup apparatus which can generate a high-definitionimage by combining the partial images obtained by picking up the targetobject in divisions. In addition, it is possible to secure the necessaryoverlapping region that is required when combining the partial images,and to instruct the operator of the parts of the target object to bepicked up so that all parts of the target object are picked up withoutdropout of image information.

Another object of the present invention is to provide an imageprocessing method for processing an image of a target object which ispicked up by an image pickup apparatus in divisions as a plurality ofpartial images which overlap by a predetermined quantity, comprising thesteps of (a) setting a field angle with which the target object is to bepicked up, (b) displaying an image, and (c) generating the partialimages to be displayed by the step (b) by dividing a full image of thetarget image which is picked up with a predetermined field angle set bythe step (a) into predetermined sizes using the predetermined fieldangle and information related to an overlap of the partial images afterthe predetermined field angle is set by the step (a). According to theimage processing method of the present invention, the two images whichare displayed in the overlapping manner in the full image areapproximately the same, so that the effect of positioning or aligningthe two images by the overlapping display is large.

Other objects and further features of the present invention will beapparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1D are diagrams for explaining a method proposed in aJapanese Laid-Open Patent Application No.11-75108;

FIGS. 2A through 2C are diagrams for explaining the method proposed inthe Japanese Laid-Open Patent Application No.11-75108;

FIG. 3 is a diagram for explaining the method proposed in the JapaneseLaid-Open Patent Application No.11-75108;

FIG. 4 is a diagram for explaining a first embodiment of an image pickupapparatus according to the present invention;

FIG. 5 is a flow chart for explaining the operation of the firstembodiment of the image pickup apparatus;

FIG. 6 is a flow chart for explaining the image combining operation ofthe first embodiment of the image pickup apparatus;

FIGS. 7A through 7C are diagrams for explaining the combining of partialimages in the first embodiment of the image pickup apparatus;

FIG. 8A through 8E are diagrams for explaining partial images which arepicked up by the first embodiment of the image pickup apparatus;

FIG. 9 is a flow chart for explaining the operation of the firstembodiment of the image pickup apparatus in a partial image pickup mode;

FIGS. 10A and 10B are diagrams for explaining a division of a full imagein the first embodiment of the image pickup apparatus;

FIG. 11 is a diagram for explaining the division of the full image inthe first embodiment of the image pickup apparatus;

FIGS. 12A through 12E are diagrams showing menus which are displayed insecond, third, fifth, seventh and ninth embodiments of the image pickupapparatus according to the present invention;

FIG. 13 is a diagram showing a display made in the first through tenthembodiments of the image pickup apparatus according to the presentinvention;

FIG. 14 is a diagram showing a display made in an eleventh embodiment ofthe image pickup apparatus according to the present invention; and

FIG. 15 is a flow chart for explaining the operation of a fourteenthembodiment of the image pickup apparatus according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 4 is a diagram for explaining a first embodiment of an image pickupapparatus according to the present invention. This first embodiment ofthe image pickup apparatus employs a first embodiment of an imageprocessing method according to the present invention. In this firstembodiment, the present invention is applied to an image pickupapparatus made of a digital camera.

In FIG. 4, an image of a target object is imaged on a surface of animage pickup element 11 via a lens 10, and the image is converted intoan image signal by the image pickup element 11. The image signal fromthe image pickup element 11 is converted into a digital image signal byan analog-to-digital (A/D) converter 12, and is supplied to a MPU 13which functions as a signal processing means and a control means.

The MPU 13 carries out various processes, including a correction processand a compression process, with respect to the digital image signalreceived via the A/D converter 12, and stores the processed image signalin an image memory 14. A display unit 15 is made of a liquid crystaldisplay (LCD) or the like, and displays an image under the control ofthe MPU 13, such as an image (through-image) which is presently beingpicked up by the image pickup element 11, the image immediately prior tobeing stored in the image memory 14, and the image stored in the imagememory 14.

A field angle setting unit 16 variably sets a field angle with which theimage is to be picked up, by varying a zoom magnification by varying afocal distance of the lens 10 in response to an instruction from theoperator. In this state, the field angle setting unit 16 supplies afield angle varying signal to a zoom mechanism 17 via the MPU 13, andthe zoom mechanism 17 varies the focal distance of the lens 10 bydriving the lens 10 and the like in response to the field angle varyingsignal.

An interface (I/F) 18 forms an interface for functions other thanvarying the field angle. The interface 18 includes a LED 100 which turnsON during a normal image pickup mode, a LED 101 which turns ON during apartial (or divided) image pickup mode, a switch 102 which is pushed toswitch the image pickup mode to the normal image pickup mode, a switch103 which is pushed to switch the image pickup mode to the partial (ordivided) image pickup mode, a power switch 104 which is pushed to turnthe power supply ON/OFF, a LCD 105 for displaying the state of thecamera, a LED 106 which turns ON when a divided image is beingdisplayed, and a LED 107 which is turned ON when a through image isbeing displayed. Although omitted in FIG. 4, the interface 18 alsoincludes an image switching unit and manipulation buttons which will bedescribed later. The image switching unit may be formed by one or moreswitches.

The divided image is an image which is obtained when the full (orentire) image of a target object is divided according to the presentinvention, and is displayed as a guide when picking up a partial image.The partial image is an image which is obtained by picking up only apart of the target object or, an image which is to be obtained bypicking up only a part of the target object. The through image is amotion picture which is continuously picked up, and is continuouslydisplayed on the display unit 15. The through image is not held in theimage memory 14.

A release button 19 is coupled to the MPU 13, and is manipulated wheninputting the image. Further, a distance sensor 20 is coupled to the MPU13 for detecting and inputting a distance to a target object which ismeasured by a known means.

Next, a description will be given of the operation of this firstembodiment when combining partial images. FIG. 5 is a flow chart forexplaining the operation of the MPU 13 of this first embodiment.

In FIG. 5, a step S1 decides whether an image pickup is to be carriedout in divisions, that is, in the partial image pickup mode. When theimage of the target object is to be picked up in divisions, the operatorspecifies the partial image pickup mode from the mode switching unit 19.If the operator specifies the normal image pickup mode, the decisionresult in the step S1 is NO, and the image of the target object ispicked up as in the case of the conventional image pickup apparatus.That is, in the normal image pickup mode, the image of the target objectis picked up as it is without being divided, by use of the lens 10, theimage pickup element 11, the A/D converter 12, the MPU 13, the displayunit 15 and the field angle setting unit 16. An image signal of theimage of the target object picked up in the normal image pickup mode isstored in the image memory 14 and is displayed on the display unit 15.

On the other hand, if the operator specifies the partial image pickupmode, the decision result in the step S1 is YES, and a step S2 carriesout a partial image pickup operation. More particularly, the step S2picks up the image of the target object in divisions, that is, picks uppartial images of the target object. The partial images of the targetobject are picked up by use of the field angle setting unit 16, the lens10, the image pickup element 11, the A/D converter 12 and the MPU 13.Image signals of the partial images are stored in the image memory 14.Thereafter, a step S3 carries out an image combining operation. In otherwords, the step S3 combines the partial images by the MPU 13, andgenerates a single combined image. An image signal of this singlecombined image is stored in the image memory 14.

Next, a description will be given of the contents processed during theimage combining operation. FIG. 6 is a flow chart for explaining theimage combining operation of the step S3 shown in FIG. 5. In addition,FIGS. 7A through 7C are diagrams for explaining the combining of partialimages in this first embodiment. For the sake of convenience, a partialimage of the target object is denoted by P(i), where i=1, . . . , N, andit is assumed that a total of N partial images of the target objectexist.

In FIG. 6, a step S11 loads a partial image P(1) by setting i to i=1,and a step S12 extracts feature points on the partial image P(i). Inother words, the MPU 13 reads the partial image P(1) from the imagememory 14, and automatically detects the feature points on the partialimage P(1). If the partial image P(1) is as shown in FIG. 7A, it isdesirable to extract corner portions 21 through 24 of the partial imageP(1) indicated by circular marks as the feature points. Such featurepoints can be detected by use of a differentiating filter or the like.

Next, a step S13 loads a partial image P(i+1) which is adjacent to thepartial image P(i), and a step S14 extracts feature points on thepartial image P(i+1) corresponding to the feature points on the partialimage P(i). More particularly, the MPU 13 reads the partial image P(2)which is adjacent to the partial image P(1) from the image memory 14,and extracts feature points 21′ through 24′ of the partial image P(2)which respectively correspond to the feature points 21 through 24 of thepartial image P(1) and are indicated by circular marks in FIG. 7B. Thecorresponding feature points 21′ through 24′ can be extracted byobtaining correlation values (correlation values between the partialimage P(1) and P(2)) of small image regions about the feature points 21through 24 on the partial image P(1) on the partial image P(2), andextracting as the corresponding feature points 21′ through 24′ thecenters of the regions where the correlation values become a localmaximum.

A step S15 calculates projection conversion parameters. If a coordinateof a certain point on the partial image P(1) is denoted by (x, y) and acorresponding coordinate on the corresponding partial image P(2) isdenoted by (x′, y′), the following formulas (1) stand when the targetobject is a plane such as the paper surface or the wall or a distantobject, where h0 through h7 are called projection conversion parameterswhich are constants peculiar between two images.x=(h 0·x′+h 1·y′+h 2)/(h 6·x′+h 7·y′+1)y=(h 3−x′+h 4−y′+h 5)/(h 6−x′+h 7−y′+1)  (1)

Accordingly, the projection conversion parameters h0 through h7 can beobtained if four or more pairs of corresponding feature points of thepartial images P(1) and P(2) exist. In general, several tens of pairs ofcorresponding feature points of the partial images P(1) and P(2) areused since noise is included in the images, and the MPU 13 calculatesthe projection conversion parameters h0 through h7 from the pairs ofcorresponding feature points by the method of least squares.

A step S16 combines the partial images P(i) and P(i+1) into a singleimage based on the calculated projection conversion parameters h0through h7, using the formulas (1) described above, and newly definesthe single image as P(i+1). In this particular case, the MPU 13generates a single image by combining the partial images P(1) and P(2)based on the relationships of the feature points 21 through 24 of thepartial image P(1) and the corresponding feature points 21′ through 24′of the partial image P(2), that is, the projection conversion parametersh0 through h7, using the formulas (1). Hence, the single image shown inFIG. 7C is generated when the partial images P(1) and P(2) respectivelyshown in FIGS. 7A and 7B are combined.

Therefore, when the projection conversion parameters h0 through h7 arecalculated, the MPU 13 uses the formulas (1) to calculate the positionsof all of the pixels of the partial image P(2) on the partial imageP(1). Hence, the partial images P(1) and P(2) can be appropriatelycombined into the single image which is newly defined as P(2).

A step S17 increments i by one to i=i+1, and a step S18 decides whetheror not i=N. The process returns to the step S12 if the decision resultin the step S18 is NO. The process ends if the decision result in thestep S18 is YES.

Hence, the MPU 13 repeats the above described operation until all of thepartial images are combined into the single image. As a result, it ispossible to generate a high-definition image.

Of course, it is not essential for the image combining operation to becarried out in the image pickup apparatus. The partial images may betransferred to an information processing apparatus such as a personalcomputer, so that the image combining operation is carried out in thepersonal computer.

In addition, if a distortion is introduced in the generatedhigh-definition image, it is possible to correct the distortion manuallyor by use of the projection conversion parameters.

Next, a description will be given of the operation of this firstembodiment in the partial image pickup mode, by referring to FIGS. 8Athrough 8E and 9. FIG. 8A through 8E are diagrams for explaining thepartial images which are picked up by this first embodiment. Inaddition, FIG. 9 is a flow chart for explaining the operation of thisfirst embodiment in the partial image pickup mode, that is, the partialimage pickup operation of the step S2 shown in FIG. 5.

First, the full image of the object shown in FIG. 8A is picked up by useof the field angle setting unit 16, the lens 10, the image pickupelement 11, the A/D converter 12, the MPU 13 and the display unit 15. Inthis state, the field angle with which the image pickup is made is setby the field angle setting unit 16 so that the full image of the objectcan be picked up.

Next, in order to pickup a partial image corresponding to a dividedimage shown in FIG. 8B which is obtained by dividing the full image ofthe object, the MPU 13 displays on the display unit 15 at the time ofthe monitoring a divided image indicated by a dotted line and athrough-image indicated by a solid line in an overlapping manner asshown in FIG. 8D, so as to input a partial image similar to the dividedimage shown in FIG. 8B. Similarly, in order to pickup a partial imagecorresponding to a divided image shown in FIG. 5C which is obtained bydividing the full image of the object, the MPU 13 displays on thedisplay unit 15 at the time of the monitoring a divided image indicatedby a dotted line and a through-image indicated by a solid line in anoverlapping manner as shown in FIG. 8E, so as to input a partial imagesimilar to the divided image shown in FIG. 8C.

In FIG. 9, a step S21 sets the image pickup apparatus to a full fieldangle setting state to set the field angle for picking up the full imageof the target object. In this full field angle setting state, theoperator operates the field angle setting unit 16 so as to determine thefield angle for picking up the full image of the target object. Then, astep S22 picks up the full image of the target object. Moreparticularly, the operator pushes the release button 19, so that theimage pickup apparatus escapes from the full field angle setting state.The full image of the target object is picked up by the image pickupelement 11 via the lens 10, and the image signal from the image pickupelement 11 is supplied to the MPU 13 via the A/D converter 12. Hence,the digital image signal is subjected to various processes such as thecorrection process and the compression process in the MPU 13, and theprocessed digital image signal is stored in the image memory 14.

Next, a step S23 sets the image pickup apparatus to a partial fieldangle setting state to set the field angle for picking up the partialimage of the target object. In this partial field angle setting state ofthe image pickup apparatus, the operator operates the field anglesetting unit 16 so as to determine the field angle for picking up thepartial image of the target object. In this embodiment, the image pickupapparatus assumes a divided image generating state when the end of thesetting of the partial field angle is notified from the field anglesetting unit 16 to the MPU 13. The end of the setting of the partialfield angle may be notified by operating the interface 18 or, by issuingan end notification if no operation is carried out to change the fieldangle for a predetermined time. Thereafter, it is possible to takemeasures so that the image pickup apparatus returns to the partial fieldangle setting state if the field angle is changed again.

In the divided image generating state, the MPU 13 carries out anoperation to divide the full image stored in the image memory 14, bysteps S24 through S28 shown in FIG. 9. The step S24 sets i to i=1, andthe step S25 displays a divided image Q(i). The step S26 picks up apartial image P(i). The step S27 increments i to i=i+1, and the step S28decides whether or not i=N. The process returns to the step S25 if thedecision result in the step S28 is NO. The process ends if the decisionresult in the step S28 is YES. The steps S24 through S28 carried out inthe divided image generating state will be described later in moredetail.

A description will be given of the division of the full image. FIGS.10A, 10B and 11 are diagrams for explaining the division of the fullimage in this first embodiment.

As shown in FIG. 10A, when the full image of a target object O is pickedup, the full image is imaged on the image pickup element 11 in a range11. In this state, it is assumed for the sake of convenience that thelens 10 has a focal distance fa. On the other hand, when the partialfield angle is set in the field angle setting unit 16 in the partialfield angle setting state as shown in FIG. 10B, the partial image isimaged on the image pickup element 11 in a range lp. In this state, itis assumed for the sake of convenience that the lens 10 has a focaldistance fp.

A ratio of the length of the partial image with respect to the length ofthe full image can be described by lp/la=fa/fp. Accordingly, when thelength of the full image is denoted by 1 as shown in FIG. 11, the lengthof the divided image becomes fa/fp. The number of divided images isdetermined so that each divided image has an overlapping region. If aminimum required length of the overlapping region is denoted by d1, anumber mx of divisions of the image in the horizontal direction isdetermined as an integer which makes the following formula (2) greaterthan or equal to one and a positive integer closest to one.(mx−1){(fa/fp)−d}+(fa/fp)  (2)

In this state, the minimum required length d1 is used for d. If a numbermx which makes the formula (2) exactly equal to one does not exist, d istreated as an unknown after determining the number mx, and d2 is usedfor d so that the formula (2) becomes equal to one. In this case, d2becomes greater than d1, and the overlapping region increases. Althoughthe number mx of divisions in the horizontal direction of the image isdetermined in the above described case, a number my of divisions in thevertical direction of the image is generally the same as the number mx.However, if the minimum required length of the overlapping regiondiffers between the horizontal divisions and the vertical divisions, thenumber my is obtained by carrying out a calculation similar to thatcarried out to obtain the number mx, but by use of the minimum requiredlength of the overlapping region for the vertical division. Therefore,the number of divisions of the full image amounts to a total of mx×my.

In the divided image generating state, the MPU 13 reads the full imagefrom the image memory 14, and divides the full image so that the dividedimages partially overlap. As a result, N=mx×my divided images Q(i) aregenerated, where i=1, 2, . . . , N. Next, the MPU 13 displays thedivided image Q(i) on the display unit 15, and urges the operator topick up an image similar to the divided image Q(i). In this state, theMPU 13 may carry out an appropriate interpolation process on the dividedimage Q(i), so as to make an enlarged display of the divided image Q(i)with an appropriate magnification of fp/fa, for example. A constantvalue which is obtained through experience may be used for the minimumrequired length d1 or, the value of the minimum required length d1 maybe varied depending on the kind of image.

The operator carries out an operation to pick up and record a part ofthe target object which approximately matches the divided image Q(i),while viewing the divided image Q(i) on the display unit 15. If theminimum required overlapping region is set with a sufficient margin, aslight error between the picked up partial image P(1) and the dividedimage Q(i) will not cause problems. By this operation carried out by theoperator, the partial image P(1) is picked up in the above describedmanner by use of the lens 10, the image pickup element 11, the A/Dconverter 12, the MPU 13 and the display unit 15, and is recorded in theimage memory 14. The above described operation is successively carriedout with respect to all of the N divided images, and thus, the partialimages P(1) through P(N) are successively picked up and recorded in theimage memory 14. Each of the above states, that is, the image number ofeach partial image which is picked up, may be notified to the operatorusing the interface 18, by indicating the image number of the partialimage which is being picked up. In addition, all of the divided imagesmay be generated immediately after the full image is picked up or, maybe generated immediately before being displayed for picking up thepartial image. Furthermore, it is possible to provide a means fordisplaying a position of each divided image on the full image.

Therefore, this first embodiment of the image pickup apparatus includesthe field angle setting unit 16 which functions as the field anglesetting means for setting the field angle with which the image is to bepicked up, and the display unit 15 which functions as the display meansfor displaying the image, and the target object is picked up as thepartial images which are obtained by dividing the target object into aplurality of divisions with a predetermined overlap quantity. The imagepickup apparatus further includes the MPU 13 which functions as a meansfor generating the partial image displayed on the display unit 15 bydividing the full image of the picked up target object intopredetermined sizes by setting the field angle to a predetermined fieldangle by the field angle setting unit 16, using the field angle andoverlap information of the partial images after the field angle settingunit 16 sets the field angle, so that the high-definition image can begenerated by combining the partial images of the target object. Hence,the necessary overlapping region can be secured when combining thepartial images, and it is possible to instruct the operator of the partsof the target object to be picked up so that all parts of the targetobject are picked up. In addition, by displaying the divided image whichclosely resembles the partial image which is to be picked up and urgingthe operator to pick up a similar image (partial image), it is possibleto automatically secure the necessary overlap quantity for combining thepartial images, without requiring the operator to be aware of such, andall parts of the target object are positively picked up without adropout. Accordingly, compared to the conventional methods, it ispossible to reduce the burden on the operator, and the required amountof processing can be suppressed to a realistic or tolerable amountexecutable within a camera.

In this first embodiment, the overlapping region of each divided imagehas the predetermined length, but this predetermined length may ofcourse be freely varied when the operator makes the image pickup.

Next, a description will be given of a second embodiment of the imagepickup apparatus according to the present invention. In this second andsubsequent embodiments of the image pickup apparatus, the basicstructure of the first embodiment of the image pickup apparatus shown inFIG. 4 may be used, and thus, a description of the basic structure willbe omitted for these embodiments. In addition, the second and subsequentembodiments of the image pickup apparatus respectively employ second andsubsequent embodiments of the image processing method according to thepresent invention.

In this second embodiment, the operator can freely vary the length ofthe overlapping region of each divided image in the first embodimentdescribed above. More particularly, when a manipulating button withinthe interface 18 is pushed, the MPU 13 displays a menu shown in FIG. 12Aon the display unit 15. When a “overlap quantity” on the menu isspecified by the manipulation button within the interface 18, the MPU 13changes the length of the overlapping region of each divided image to adesired overlap quantity which is prestored or specified.

According to this second embodiment, the manipulation button within theinterface 18 functions as an overlap quantity specifying means forspecifying the amount of overlap of the partial images. Hence, it ispossible to pick up the partial images so as to improve the accuracy ofcombining the partial images while taking into consideration theavailable storage capacity. Each partial image must have an overlappingregion to a certain extent, regardless of the target object. Moreover,depending on the target object, a success rate of the subsequent partialimage combining process deteriorates unless the overlapping region isincreased. In the conventional methods, the amount of overlapping regionto be secured depends solely on the skill and experience of theoperator. But in this second embodiment, the predetermined overlappingregion can accurately be secured automatically, and the overlap quantitycan be set arbitrarily to secure the desired overlap quantity and tofurther improve the effects of the overlapping region.

In the first and second embodiments described above, the field anglewith which the partial image is picked up is set manually by theoperator. However, the field angle with which the partial image ispicked up may be set automatically to a predetermined field angle.

Next, a description will be given of a third embodiment of the imagepickup apparatus according to the present invention. In this thirdembodiment, the field angle with which the partial image is picked up isset automatically to a predetermined field angle in the first embodimentdescribed above.

More particularly, when a manipulating button within the interface 18 ispushed, the MPU 13 displays a menu shown in FIG. 12B on the display unit15. When a “focal distance” on the menu is specified by the manipulationbutton within the interface 18, the MPU 13 changes the focal distance ofthe lens 10 to a desired focal distance which is prestored or specified.In the field angle setting state, the MPU 13 controls the zoom mechanism17 so that the focal distance of the lens 10 becomes 100 mm, forexample, so as to automatically set the field angle to the predeterminedfield angle, and the changes the image pickup apparatus to the nextstate.

Next, a description will be given of a fourth embodiment of the imagepickup apparatus according to the present invention. In this fourthembodiment, the field angle with which the partial image is picked up isset automatically to a predetermined field angle in the secondembodiment described above, in a manner similar to that of the thirdembodiment.

Therefore, according to the third and fourth embodiments, it is possibleto easily set the field angle with which the partial image is to bepicked up in the first and second embodiments described above,respectively, because the MPU 13 functions as a means for automaticallysetting the field angle with which the partial image is to be picked upto a predetermined field angle. In addition, although the field angleused to pick up the partial image differs depending on the individualoperator, it is possible to set the field angle arbitrarily. For thisreason, it is possible to further reduce the burden on the operator, byautomatically setting the field angle when picking up the image of thetarget object in divisions.

In the third and fourth embodiments described above, the focal distanceof the lens 10 is set directly in order to set field angle. However, itis possible to set the field angle by setting the resolution with whichthe image pickup is to be made.

Next, a description will be given of a fifth embodiment of the imagepickup apparatus according to the present invention. In this fifthembodiment, the field angle with which the partial image is picked up isset automatically to a predetermined field angle in the third embodimentdescribed above, by setting the resolution with which the partial imageis to be picked up.

More particularly, when a manipulating button within the interface 18 ispushed, the MPU 13 displays a menu shown in FIG. 12C on the display unit15. When a “resolution” on the menu is specified by the manipulationbutton within the interface 18, the MPU 13 changes the resolution to adesired resolution which is prestored or specified. The resolution isset to 200 dpi, for example.

The “focal distance” displayed on the menu shown in FIG. 12C may beswitched automatically to read “automatic” when the value of the“resolution” is input, and other items displayed on the menu maysimilarly be switched automatically. The distance sensor 20 functions asa distance measuring means for measuring the distance to the targetobject. The MPU 13 uses a distance l to the target object measured bythe distance sensor 20 and a resolution r which is specified by themanipulating button within the interface 18, to calculate the focaldistance fp with which the partial image is to be picked up based on thefollowing formula (3), where e denotes a pixel pitch of the image pickupelement 11.fp=(r·l)/e  (3)

The MPU 13 controls the zoom mechanism 17 by the focal distance fp whichis calculated according to the formula (3), so as to set the fieldangle. Of course, it is possible to use a known distance sensor which isused for automatic focusing in common as the distance sensor 20.

Next, a description will be given of a sixth embodiment of the imagepickup apparatus according to the present invention. In this sixthembodiment, the field angle with which the partial image is picked up isset automatically to a predetermined field angle in the fourthembodiment described above, by setting the resolution with which thepartial image is to be picked up.

More particularly, when a manipulating button within the interface 18 ispushed, the MPU 13 displays a menu similar to that shown in FIG. 12C onthe display unit 15. When a “resolution” on the menu is specified by themanipulation button within the interface 18, the MPU 13 changes theresolution to a desired resolution which is prestored or specified.

According to the fifth and sixth embodiments, the manipulating buttonwithin the interface 18 functions as a resolution specifying means forspecifying the resolution, and the distance sensor 20 functions as thedistance measuring means for measuring the distance to the targetobject. In addition, the MPU 13 functions as a means for setting thefield angle to a predetermined value by calculating the field angle fromthe resolution specified by the resolution specifying means and thedistance measured by the distance measuring means. Consequently, it ispossible to easily specify the field angle with which the partial imageis to be picked up. Although the resolution to be used differs dependingon the target object which is to be picked up by the image pickupapparatus, it is possible to arbitrarily set the resolution, therebymaking it possible to further reduce the burden on the operator.

Next, a description will be given of a seventh embodiment of the imagepickup apparatus according to the present invention. In this seventhembodiment, the size of the target object is set in addition to theresolution in the fifth embodiment described above, without the use ofthe distance sensor 20.

More particularly, when a manipulating button within the interface 18 ispushed, the MPU 13 displays a menu shown in FIG. 12D on the display unit15. When the “resolution” and a “target object size” on the menu arespecified by one or more manipulation buttons within the interface 18,the MPU 13 changes the resolution to a desired resolution which isprestored or specified, and also changes the target object size to adesired size. For example, the resolution is set to 200 dpi, and thetarget object size is set to A4-size horizontal or B5-size vertical. Thetarget object size may be specified by the manipulation button withinthe interface 18 to a standardized paper size or, the size itself suchas the length may be input directly.

In this seventh embodiment, the MPU 13 calculates the focal distance fpfor picking up the partial image based on the following formula (4),using the length la of the target object determined by the target objectsize which is input via the manipulating button within the interface 18and the set resolution r, where g denotes a number of pixels of theimage pickup element 11 along a direction corresponding to the targetobject length la. The MPU 13 sets the field angle by controlling thezoom mechanism 17 based on the focal distance fp which is calculatedaccording to the formula (4).fp=(r·fa·la)/g  (4)

Next, a description will be given of an eighth embodiment of the imagepickup apparatus according to the present invention. In this eighthembodiment, the size of the target object is set in addition to theresolution in the sixth embodiment described above, similarly to theseventh embodiment, without the use of the distance sensor 20.

Therefore, according to the seventh and eighth embodiments, themanipulating button within the interface 18 functions as a target objectsize specifying means for specifying the size of the target object, andthe manipulating button within the interface 18 functions as aresolution setting means for setting the resolution by specifying orstoring the resolution. In addition, the MPU 13 functions as a means forsetting the field angle to a predetermined value by calculating thefield angle from the target object size specified by the target objectsize specifying means and the resolution specified by the resolutionspecifying means. Consequently, it is possible to easily specify thefield angle with which the partial image is to be picked up. Inaddition, since it is possible to set the size of the target object andit is thus unnecessary to provide the distance sensor 20, it is possibleto reduce both the size and cost of the image pickup apparatus.

Next, a description will be given of a ninth embodiment of the imagepickup apparatus according to the present invention. In this ninthembodiment, the number of divisions of the target object is set in thefifth embodiment described above.

More particularly, when a manipulating button within the interface 18 ispushed, the MPU 13 displays a menu shown in FIG. 12E on the display unit15. When a “number of divisions” on the menu is specified by themanipulation button within the interface 18, the MPU 13 sets the numberof divisions to a desired number of divisions. For example, the numberof divisions is set to three. The number of divisions in one directionis set in this ninth embodiment. Hence, the actual number of divisionsis 3×3=9. Of course, the number of divisions may be specified to thetotal number of partial images.

The MPU 13 calculates the focal distance fp with which the partial imageis to be picked up, by solving the formula (5) using the number mx ofdivisions of the target object in one direction specified by themanipulating button within the interface 18. In addition, the MPU 13sets the field angle by controlling the zoom mechanism 17 based on thefocal distance fp which is calculated according to the formula (5).(mx−1){(fa/fp)−d 1}+(fa/fp)=1  (5)

Next, a description will be given of a tenth embodiment of the imagepickup apparatus according to the present invention. In this tenthembodiment, the number of divisions of the target object is set in thesixth embodiment described above, similarly to the ninth embodiment.

Therefore, according to the ninth and tenth embodiments, it is possibleto easily specify the field angle with which the partial image is to bepicked up in the fifth and sixth embodiments, respectively, by providingin the image pickup apparatus the manipulating button within theinterface 18 having the function of a division number specifying meansfor specifying the number of divisions of the full image of the targetobject, and the MPU 13 which functions as a means for setting the fieldangle to a predetermined field angle by calculating the field angle fromthe number of divisions specified by the division number specifyingmeans. The time required to pick up the full image of the target objectincreases and the storage capacity required to store the partial imagesincreases as the number of partial images increases. However, by settingthe number of partial images to be recorded, it is possible to preventsuch problems in advance by predicting the time required to pick up thefull image and the storage capacity required to store the partialimages.

It is desirable that each setting made in the second through tenthembodiments described above occurs prior to the partial image pickupmode. In addition, when a certain item is set on the menu which isdisplayed on the display unit 15, an item which is automaticallydetermined thereby or cannot be decided may be indicated as being“invalid”, for example.

According to the first through tenth embodiments described above, theMPU 13 displays on the display unit 15 a divided image indicated by adotted line and a through-image indicated by a solid line in anoverlapping manner as shown in FIG. 13. In this state, the divided imageis displayed on an enlarged scale which is fp/fa times, as describedabove. The operator picks up the image of the target object by varyingthe position and direction of the image pickup apparatus (camera) sothat the divided image and the through-image match as much as possible.By repeating such an operation, it is possible to pick up the partialimages without missing image portions of the target object, withappropriate overlapping regions among the partial images without havingthe operator be positively aware of forming such overlapping regions.The divided image may be subjected to an image processing such as anedge emphasis process, so that it is easier to match the positions ofthe divided image and the through-image. Further, the tone value of oneof the through-image and the divided image may be reduced or, one of thethrough-image and the divided image may be displayed in black-and-white,so as to facilitate the operator distinguish the through-image and thedivided image.

Moreover, according to the first through tenth embodiments, the displayunit 15 functions as the display means for simultaneously displaying thedivided image and the image which is presently being picked up in anoverlapping manner. Hence, it is possible to facilitate the recognitionof the divided image by the operator when picking up the partial image.In the conventional methods, the through-image and the divided image aredisplayed to only partially overlap or, the through-image is displayedto partially overlap another adjacent image, thereby making it difficultto recognize and position the images. But in the first through tenthembodiments, the two images which are displayed in the overlappingmanner in the full image are approximately the same, so that the effectof positioning or aligning the two images by the overlapping display islarge.

Next, a description will be given of an eleventh embodiment of the imagepickup apparatus according to the present invention. In this eleventhembodiment, the MPU 13 displays the through-image on the display unit 15on a large scale as shown in FIG. 14, and displays the divided image onan appropriately enlarged or reduced scale in a part of the display madeon the display unit 15, in the first embodiment described above. FIG. 14shows a case where the divided image is displayed on a reduced scale ata top left part of the display made on the display unit 15. The operatorpicks up the image while comparing the scaled divided image and thethrough-image on the display and varying the camera position anddirection so that the two images become approximately the same. Byrepeating such an operation, it is possible to pick up the partialimages which automatically overlap without dropout of image informationrelated to the target object.

Next, a description will be given of a modification of the eleventhembodiment of the image pickup apparatus. In this modification of theeleventh embodiment, the MPU 13 displays the through-image on thedisplay unit 15 on a large scale, and displays the divided image on anappropriately enlarged or reduced scale in a part of the display made onthe display unit 15, similarly to the eleventh embodiment, in the any ofthe second through tenth embodiments described above.

In the eleventh embodiment and the modification thereof, the dividedimage may be displayed on the display unit 15 on a large scale and thethrough-image may be displayed in a part of the display made on thedisplay unit 15, or alternatively, the divided image and thethrough-image may be displayed side-by-side on the display unit 15.Furthermore, the divided image and the through-image may be displayed oncorresponding display units by providing two display units.

Therefore, according to the eleventh embodiment and the modificationthereof, the image pickup apparatus according to any of the firstthrough tenth embodiments simultaneously displays the divided image andthe image which is presently being picked up at different positions onthe display unit 15 which functions as a display means. For this reason,the operator can easily recognize the divided image when picking up thepartial image. The display unit 15 provided on the image pickupapparatus is often small and the display made thereon is difficult tosee, particularly when two images are simultaneously displayed thereon.In the conventional methods, the images that are compared only are thesame in part, and if two images are simultaneously displayed separately,it is extremely difficult to visually recognize the end portions whichare the same, thereby increasing the possibility of making errors duringthe image pickup-operation. But in the eleventh embodiment and themodification thereof, the two images that are compared are approximatelythe same, and the two images are compared in the full image.Consequently, the visual recognition does not greatly deteriorate evenif two images are simultaneously displayed, thereby preventing theoperator from making errors during the image pickup operation.

Next, a description will be given of a twelfth embodiment of the imagepickup apparatus according to the present invention. In this twelfthembodiment, the MPU 13 displays the divided image and the through-imagetime-divisionally at predetermined time intervals at the same positionon the display unit 15, in the first embodiment described above. Theoperator picks up the image while comparing the divided image and thethrough-image which are time-divisionally displayed and varying thecamera position and direction so that the two images becomeapproximately the same. By repeating such an operation, it is possibleto pick up the partial images which automatically overlap withoutdropout of image information related to the target object.

Next, a description will be given of a modification of the twelfthembodiment of the image pickup apparatus. In this modification of thetwelfth embodiment, the MPU 13 displays the divided image and thethrough-image time-divisionally at predetermined time intervals at thesame position on the display unit 15, similarly to the twelfthembodiment, in any of the second through tenth embodiments describedabove.

In the twelfth embodiment and the modification thereof, it is possibleto add an indication to at least one of the divided image and thethrough-image, so that it is possible to positively distinguish the twoimages. For example, the MPU 13 may display an indication whichindicates the kind of image on the lower part of each of the dividedimage and through-image or, turn ON the LEDs 106 and 107 correspondingto the respective images.

Therefore, according to the twelfth embodiment and the modificationthereof, the image pickup apparatus according to any one of the firstthrough tenth embodiments displays the divided image and thethrough-image time-divisionally at predetermined time intervals at thesame position on the display unit 15 which functions as a display means,and thus, it is possible to facilitate the recognition of the dividedimage by the operator when picking up the partial image. The displayunit 15 provided on the image pickup apparatus is often small and thedisplay made thereon is difficult to see and recognize. In theconventional methods, the images that are compared only are the same inpart, and if two images are time-divisionally displayed, it is extremelydifficult to visually recognize the end portions which are the same,thereby increasing the possibility of making errors during the imagepickup operation. But in the twelfth embodiment and the modificationthereof, the two images that are compared are approximately the same,and the two images are compared in the full image. Consequently, thevisual recognition does not greatly deteriorate even if two images aretime-divisionally displayed, thereby preventing the operator from makingerrors during the image pickup operation.

Next, a description will be given of a thirteenth embodiment of theimage pickup apparatus according to the present invention. In thisthirteenth embodiment, an image switching unit within the interface 18arbitrarily switches the display on the display unit 15 via the MPU 13between the divided image and the through-image, in response to anoperation carried out by the operator on the image switching unit, inthe first embodiment described above. The operator picks up the imagewhile comparing the divided image and the through-image which arearbitrarily switched and displayed and varying the camera position anddirection so that the two images become approximately the same. Byrepeating such an operation, it is possible to pick up the partialimages which automatically overlap without dropout of image informationrelated to the target object.

Next, a description will be given of a modification of the thirteenthembodiment of the image pickup apparatus. In this modification of thethirteenth embodiment, the image switching unit within the interface 18arbitrarily switches the display on the display unit 15 via the MPU 13between the divided image and the through-image, in response to theoperation carried out by the operator on the image switching unit,similarly to the thirteenth embodiment, in any of the second throughtenth embodiments described above.

In the thirteenth embodiment and the modification thereof, it ispossible to add an indication to at least one of the divided image andthe through-image, so that it is possible to positively distinguish thetwo images. For example, the MPU 13 may display an indication whichindicates the kind of image on the lower part of each of the dividedimage and through-image or, turn ON the LEDs 106 and 107 correspondingto the respective images.

According to the thirteenth embodiment and the modification thereof, theimage pickup apparatus according to any of the first through tenthembodiments includes the image switching unit within the interface 18,which functions as an image switching means for switching the display onthe display unit 15 which functions as a display means, to one of thedivided image and the image which is presently being picked up. Hence,the operator can easily recognize the divided image when picking up thepartial images. In addition, the number of features included in thetarget object may be small depending on the target object, and in suchcases, it is desirable to confirm the divided image. This thirteenthembodiment and the modification thereof can easily confirm the dividedimage at an arbitrary timing by switching the display to the dividedimage by the image switching unit within the interface 18, so that it ispossible to prevent the operator from making errors during the imagepickup operation.

Each of the first through thirteenth embodiments and the modificationsdescribed above is provided with a divided image displaying function fordisplaying the divided image when picking up the partial image. However,it is of course possible to provide two or more such divided imagedisplaying functions, so that the operator may select one of the dividedimage displaying functions.

Next, a description will be given of a fourteenth embodiment imagepickup apparatus according to the present invention. In this fourteenthembodiment of the image pickup apparatus, the operator can select theorder with which the partial images are picked up, in the firstembodiment described above.

FIG. 15 is a flow chart for explaining the operation of this fourteenthembodiment of the image pickup apparatus. The operation shown in FIG. 15is basically the same as that shown in FIG. 9 up to the divided imagegenerating state. In addition, when the image switching unit within theinterface 18 is operated by the operator, the display of the dividedimage Q(i) is successively switched.

In FIG. 15, a step S31 sets i to i=1, and a step S32 displays thedivided image Q(i). A step S33 decides whether or not the imageswitching unit within the interface 18 is operated to switch the displayof the image. If the decision result in the step S33 is YES, a step S34increments i to i=i+1, and the process returns to the step S32. On theother hand, if the decision result in the step S33 is NO, a step S35decides whether or not the release button 19 is turned ON (or pushed).The process returns to the step S33 if the decision result in the stepS35 is NO.

If the decision result in the step S35 is YES, a step S36 picks up thepartial image P(i), and a step S37 decides whether or not the image ofall of the target object is picked up without dropout of imageinformation. If the decision result in the step S37 is NO, a step S38increments i to i=i+1, and a step S39 decides whether or not a portionof the image of the target object is to be picked up since the portionis not yet picked up. The process returns to the step S38 if thedecision result in the step S39 is NO, and the process returns to thestep S32 if the decision result in the step S39 is YES. Further, theprocess ends if the decision result in the step S37 is YES.

In other words, if the partial image is already picked up and thecorresponding divided image is displayed on the display unit 15, it isdesirable that the MPU 13 makes an indication on the display unit 15 orby the LED 106 that the partial image is recorded with respect to thedivided image. When the release button 19 is pushed in a state where adesired divided image is displayed on the display unit 15, the partialimage P(i) is picked up by use of the lens 10, the image pickup element11, the A/D converter 12, the MPU 13 and the display unit 15, and theimage signal of the picked up image is recorded in the image memory 14.

In addition, the MPU 13 sets a flag which indicates whether or not thepartial image P(i) corresponding to the divided image Q(i) is picked up,that is, input or recorded, with respect to each divided image. The MPU13 uses this flag to display on the display unit 15 the divided imagecorresponding to the partial image which is not yet recorded. Such anoperation is repeated until the partial images corresponding to all ofthe divided images are input or recorded.

Next, a description will be given of a modification of the fourteenthembodiment of the image pickup apparatus. In this modification of thefourteenth embodiment, the operator can select the order with which thepartial images are picked up, in the any of the second throughthirteenth embodiments described above.

Of course, in this modification of the fourteenth embodiment, it ispossible to display only the divided image corresponding to theunrecorded partial image, even when successively switching the displayof the divided image by the image switching unit. In addition, when theimage pickup of the partial image ends and the next divided image is tobe displayed, the display of this next divided image may be successivelyregardless of whether or not the corresponding partial image is pickedup. In this case, if the partial image is already picked up and thecorresponding divided image is displayed, it is desirable to make anindication with respect to this divided image by the display unit 15 orthe LED 106 to indicate that the partial image corresponding to thisdivided image is already recorded. Furthermore, even if the partialimage is already recorded, it is desirable that an overwrite of thepartial image is possible.

Therefore, according to this modification of the fourteenth embodiment,the image switching unit functions as a partial image selecting meansfor selecting the divided image. Hence, it is possible to easily pickupthe partial image again if the image pickup of the partial image fails.In the case of an image pickup error due to unwanted hand motion, it isdesirable to pick up the partial image over again. In addition, since ittakes time to pickup the image of the target object in divisions, thereis a demand to pickup a changing portion within the target object at anappropriate timing. Accordingly, the flexibility of picking up thepartial image is improved by making it possible to arbitrarily selectthe divided image.

Next, a description will be given of a fifteenth embodiment of the imagepickup apparatus according to the present invention. In this fifteenthembodiment of the image pickup apparatus, it is possible to switch themode to the normal image pickup mode from any state of the partial imagepickup mode, in the first embodiment described above.

In this fifteenth embodiment, the MPU 13 interrupts the present partialimage pickup mode in response to the switching of the mode to the normalimage pickup mode by the switch 102 within the interface 18. The MPU 13stores the content (state) at the time when this interruption takesplace in a memory such as the image memory 14, before actually switchingthe mode to the normal image pickup mode. When the mode switching unit19 is operated again to switch the mode to the partial image pickupmode, the MPU 13 restores the stored content within the memory torestore the state at the time when the partial image pickup mode wasinterrupted, and continues the partial image pickup mode from that timeon.

Next, a description will be given of a modification of the fifteenthembodiment of the image pickup apparatus. In this modification of thefifteenth embodiment, it is possible to switch the mode to the normalimage pickup mode from any state of the partial image pickup mode, inany of the second through fourteenth embodiments described above.

In this modification of the fifteenth embodiment, the image pickupapparatus according to any of the second through fourteenth embodimentsincludes the MPU 13 and the mode switching unit 19 which functions as animage pickup interrupting means for interrupting the image pickup of thepartial image and returning the image pickup apparatus to apredetermined state. Hence, it is possible to eliminate an unnecessaryimage pickup time which would otherwise be required to pick up thepartial image again when the image pickup of the target object indivisions is interrupted. The image pickup of the target object indivisions takes time, and for this reason, the operator may miss theright timing when a normal image pickup is desired. Moreover, if theimage pickup of the target object in divisions is interrupted to carryout a normal image pickup and the image pickup in divisions isthereafter restarted all over again from the start, it is extremelytroublesome to carry out such an operation and the burden on theoperator is extremely large. But according to this modification of thefifteenth embodiment, it is possible to minimize the unnecessaryincrease of the image pickup time and to reduce the burden on theoperator, by making it possible to continue the image pickup of thetarget object in divisions even after interruption thereof.

In each of the first through fifteenth embodiments and themodifications, it is possible to omit the field angle setting unit 16,if the operator can move close to and/or mode away from the targetobject to realize the effects equivalent to those of the field anglesetting unit 16. In this case, the operator moves the position of theimage pickup apparatus when picking up the full image and when pickingup the partial image, so that the full image and the partial image arepicked up within respective ranges.

In other words, when the field angle setting unit 16 is omitted, theimage pickup apparatus for picking up the image of the target object indivisions as partial images which overlap by a predetermined quantity,generally includes the display unit 15 and the MPU 13. The display unit15 functions as a display means for displaying the image. The MPU 13functions as a partial image generating means for generating the partialimage to be displayed on the display unit 15, by dividing the full imageof the target object which is picked up in advance into predeterminedsizes using information related to the overlap of the partial images.Therefore, it is possible to realize an image pickup apparatus which cangenerate a high-definition image by combining the partial imagesobtained by picking up the target object in divisions. In addition, itis possible to secure the necessary overlapping region that is requiredwhen combining the partial images, and to instruct the operator of theparts of the target object to be picked up so that all parts of thetarget object are picked up without dropout of image information.

Further, the present invention is not limited to these embodiments, butvarious variations and modifications may be made without departing fromthe scope of the present invention.

1. An apparatus for picking up an image of a target object in divisionsas a plurality of partial images which overlap, comprising: a fieldangle setting unit configured to set a field angle with which the targetobject is to be picked up; a display unit configured to display animage; and a generating unit configured to generate the partial imagesto be displayed on the display unit by dividing an image of the targetobject which is picked up with the field angle.
 2. The apparatus asclaimed in claim 1, further comprising: a calculating unit configured tocalculate the field angle from information of the target object.
 3. Theapparatus as claimed in claim 1, further comprising: a calculating unitconfigured to calculate the field angle from information of the targetobject and a resolution.
 4. The apparatus as claimed in claim 1, furthercomprising: a calculating unit configured to calculate the field anglefrom a size of the target object and a resolution.
 5. The apparatus asclaimed in claim 4, further comprising: an object size specifying unitconfigured to specify the size of the target object.
 6. The apparatus asclaimed in claim 1, further comprising: a calculating unit configured tocalculate the field angle from a distance to the target object and aresolution.
 7. The apparatus as claimed in claim 6, further comprising:a measuring unit configured to measure the distance to the targetobject.
 8. The apparatus as claimed in claim 1, wherein the display unitsimultaneously displays a divided image and an image presently beingpicked up in an overlapping manner.
 9. A method of picking up an imageof a target object in divisions as a plurality of partial images whichoverlap, comprising: setting a field angle with which the target objectis to be picked up; displaying an image on a display unit; andgenerating the partial images to be displayed on the display unit bydividing an image of the target object which is picked up with the fieldangle.
 10. The method as claimed in claim 9, further comprising:calculating the field angle from information of the target object. 11.The method as claimed in claim 9, further comprising: calculating thefield angle from information of the target object and a resolution. 12.The method as claimed in claim 9, further comprising: calculating thefield angle from a size of the target object and a resolution.
 13. Themethod as claimed in claim 12, further comprising: specifying the sizeof the target object.
 14. The method as claimed in claim 9, furthercomprising: calculating the field angle from a distance to the targetobject and a resolution.
 15. The method as claimed in claim 14, furthercomprising: measuring the distance to the target object.
 16. The methodas claimed in claim 9, wherein the displaying comprises simultaneouslydisplaying on the display unit a divided image and an image presentlybeing picked up in an overlapping manner.
 17. An apparatus for pickingup an image of a target object in divisions as a plurality of partialimages which overlap, comprising: field angle setting means for settinga field angle with which the target object is to be picked up; displaymeans for displaying an image; and generating means for generating thepartial images to be displayed on the display unit by dividing an imageof the target object which is picked up with the field angle.
 18. Theapparatus as claimed in claim 17, further comprising: calculating meansfor calculating the field angle from information of the target object.19. The apparatus as claimed in claim 17, further comprising:calculating means for calculating the field angle from information ofthe target object and a resolution.
 20. The apparatus as claimed inclaim 17, further comprising: calculating means for calculating thefield angle from a size of the target object and a resolution.